Abstract and Introduction
Introduction
As a pulmonologist with the San Diego Veteran's Affairs hospital, Laura Crotty Alexander has probably answered every possible question about smoking. Whether her patients were looking for ways to quit or simply wondering whether their current health problems might be related to smoking, Crotty Alexander provided answers.
A couple of years ago, however, her patients began asking new questions: Are electronic cigarettes safer than conventional cigarettes, and should they switch? "I didn't have the answers. As a physician and a researcher, that was very frustrating," Crotty Alexander says.
Physicians all over the country are encountering the same questions from their patients. Out of nowhere, it seems, e-cigarettes—or electronic nicotine delivery systems, as they are formally known—are appearing at gas stations, convenience stores, and anywhere else cigarettes are sold. Advertisements claim e-cigarettes offer health benefits by helping smokers quit. All e-cigarette users inhale is "harmless water vapor."1 The e-cigarette, it would seem, takes all the risk out of smoking.
Many environmental health scientists aren't so sure. Maciej Goniewicz, a toxicologist at the Roswell Park Cancer Institute in Buffalo, New York, says, "This is vapor, but only a small proportion of it is water." Mostly, he says, it's made up of propylene glycol and/or glycerin, the main ingredients in the "e-liquid" (or "e-juice") that is vaporized inside e-cigarettes. When heated, these solvents produce an aerosol resembling cigarette smoke. Most e-liquids also contain flavorings and preservatives.
"Most of what we know about e-cigarettes is from lab studies," Goniewicz says. "We don't know about the real health effects on the users of this product, especially on long-term users."
The newness of e-cigarettes means longitudinal studies about potential health dangers are still in the distant future. Meanwhile, the existing literature about the safety of the devices consists of small studies on e-liquids and e-cigarette emissions. It remains unknown exactly how e-cigarettes and their related secondhand smoke compare with conventional cigarettes.
Despite the lack of health data, many researchers assume e-cigarettes are less dangerous than conventional cigarettes. Gerry Stimson, a public health social scientist at Imperial College London, explains, "When you burn vegetable matter, you inhale lots of nasty things into your lungs." Because e-cigarettes only heat a liquid rather than burning tobacco leaves, he says, it creates fewer hazardous particles that can be inhaled.
"The vapor does not appear to be benign, but it does seem to be the lesser of two evils when compared to cigarettes," Crotty Alexander says.
Stimson adds, "At issue is a matter of weighing up potential risks against potential health benefits. Small and sometimes not so small risks are associated with all sorts of pharmacological and other health and social interventions, but the necessary precautionary principle needs to be weighed against potential benefits."
Of course, saying something is safer than smoking cigarettes isn't exactly setting a high bar. The Centers for Disease Control and Prevention estimates that cigarette smoking causes one in five U.S. deaths each year, including deaths resulting from secondhand smoke exposure. Smoking is a leading risk factor in chronic obstructive pulmonary disease, lung cancer, and cardiovascular disease. It's the leading preventable cause of premature death in the United States and one of the leading causes around the world.